Create the dbm package from PEP 3108. #2881.

1 files changed, 533 insertions, 0 deletions

diff --git a/Modules/_gdbmmodule.c b/Modules/_gdbmmodule.c
new file mode 100644
index 0000000000..4404d2f348
--- /dev/null
+++ b/Modules/_gdbmmodule.c
@@ -0,0 +1,533 @@
+
+/* DBM module using dictionary interface */
+/* Author: Anthony Baxter, after dbmmodule.c */
+/* Doc strings: Mitch Chapman */
+
+
+#include "Python.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include "gdbm.h"
+
+#if defined(WIN32) && !defined(__CYGWIN__)
+#include "gdbmerrno.h"
+extern const char * gdbm_strerror(gdbm_error);
+#endif
+
+PyDoc_STRVAR(gdbmmodule__doc__,
+"This module provides an interface to the GNU DBM (GDBM) library.\n\
+\n\
+This module is quite similar to the dbm module, but uses GDBM instead to\n\
+provide some additional functionality. Please note that the file formats\n\
+created by GDBM and dbm are incompatible. \n\
+\n\
+GDBM objects behave like mappings (dictionaries), except that keys and\n\
+values are always strings. Printing a GDBM object doesn't print the\n\
+keys and values, and the items() and values() methods are not\n\
+supported.");
+
+typedef struct {
+    PyObject_HEAD
+    int di_size;	/* -1 means recompute */
+    GDBM_FILE di_dbm;
+} dbmobject;
+
+static PyTypeObject Dbmtype;
+
+#define is_dbmobject(v) (Py_TYPE(v) == &Dbmtype)
+#define check_dbmobject_open(v) if ((v)->di_dbm == NULL) \
+    { PyErr_SetString(DbmError, "GDBM object has already been closed"); \
+      return NULL; }
+
+
+
+static PyObject *DbmError;
+
+PyDoc_STRVAR(gdbm_object__doc__,
+"This object represents a GDBM database.\n\
+GDBM objects behave like mappings (dictionaries), except that keys and\n\
+values are always strings. Printing a GDBM object doesn't print the\n\
+keys and values, and the items() and values() methods are not\n\
+supported.\n\
+\n\
+GDBM objects also support additional operations such as firstkey,\n\
+nextkey, reorganize, and sync.");
+
+static PyObject *
+newdbmobject(char *file, int flags, int mode)
+{
+    dbmobject *dp;
+
+    dp = PyObject_New(dbmobject, &Dbmtype);
+    if (dp == NULL)
+        return NULL;
+    dp->di_size = -1;
+    errno = 0;
+    if ((dp->di_dbm = gdbm_open(file, 0, flags, mode, NULL)) == 0) {
+        if (errno != 0)
+            PyErr_SetFromErrno(DbmError);
+        else
+            PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
+        Py_DECREF(dp);
+        return NULL;
+    }
+    return (PyObject *)dp;
+}
+
+/* Methods */
+
+static void
+dbm_dealloc(register dbmobject *dp)
+{
+    if (dp->di_dbm)
+        gdbm_close(dp->di_dbm);
+    PyObject_Del(dp);
+}
+
+static Py_ssize_t
+dbm_length(dbmobject *dp)
+{
+    if (dp->di_dbm == NULL) {
+        PyErr_SetString(DbmError, "GDBM object has already been closed");
+        return -1;
+    }
+    if (dp->di_size < 0) {
+        datum key,okey;
+        int size;
+        okey.dsize=0;
+        okey.dptr=NULL;
+
+        size = 0;
+        for (key=gdbm_firstkey(dp->di_dbm); key.dptr;
+             key = gdbm_nextkey(dp->di_dbm,okey)) {
+            size++;
+            if(okey.dsize) free(okey.dptr);
+            okey=key;
+        }
+        dp->di_size = size;
+    }
+    return dp->di_size;
+}
+
+static PyObject *
+dbm_subscript(dbmobject *dp, register PyObject *key)
+{
+    PyObject *v;
+    datum drec, krec;
+
+    if (!PyArg_Parse(key, "s#", &krec.dptr, &krec.dsize) )
+        return NULL;
+
+    if (dp->di_dbm == NULL) {
+        PyErr_SetString(DbmError,
+                        "GDBM object has already been closed");
+        return NULL;
+    }
+    drec = gdbm_fetch(dp->di_dbm, krec);
+    if (drec.dptr == 0) {
+        PyErr_SetObject(PyExc_KeyError, key);
+        return NULL;
+    }
+    v = PyString_FromStringAndSize(drec.dptr, drec.dsize);
+    free(drec.dptr);
+    return v;
+}
+
+static int
+dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
+{
+    datum krec, drec;
+
+    if (!PyArg_Parse(v, "s#", &krec.dptr, &krec.dsize) ) {
+        PyErr_SetString(PyExc_TypeError,
+                        "gdbm mappings have string indices only");
+        return -1;
+    }
+    if (dp->di_dbm == NULL) {
+        PyErr_SetString(DbmError,
+                        "GDBM object has already been closed");
+        return -1;
+    }
+    dp->di_size = -1;
+    if (w == NULL) {
+        if (gdbm_delete(dp->di_dbm, krec) < 0) {
+            PyErr_SetObject(PyExc_KeyError, v);
+            return -1;
+        }
+    }
+    else {
+        if (!PyArg_Parse(w, "s#", &drec.dptr, &drec.dsize)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "gdbm mappings have byte string elements only");
+            return -1;
+        }
+        errno = 0;
+        if (gdbm_store(dp->di_dbm, krec, drec, GDBM_REPLACE) < 0) {
+            if (errno != 0)
+                PyErr_SetFromErrno(DbmError);
+            else
+                PyErr_SetString(DbmError,
+                                gdbm_strerror(gdbm_errno));
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static PyMappingMethods dbm_as_mapping = {
+    (lenfunc)dbm_length,		/*mp_length*/
+    (binaryfunc)dbm_subscript,          /*mp_subscript*/
+    (objobjargproc)dbm_ass_sub,         /*mp_ass_subscript*/
+};
+
+PyDoc_STRVAR(dbm_close__doc__,
+"close() -> None\n\
+Closes the database.");
+
+static PyObject *
+dbm_close(register dbmobject *dp, PyObject *unused)
+{
+    if (dp->di_dbm)
+        gdbm_close(dp->di_dbm);
+    dp->di_dbm = NULL;
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+/* XXX Should return a set or a set view */
+PyDoc_STRVAR(dbm_keys__doc__,
+"keys() -> list_of_keys\n\
+Get a list of all keys in the database.");
+
+static PyObject *
+dbm_keys(register dbmobject *dp, PyObject *unused)
+{
+    register PyObject *v, *item;
+    datum key, nextkey;
+    int err;
+
+    if (dp == NULL || !is_dbmobject(dp)) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+    check_dbmobject_open(dp);
+
+    v = PyList_New(0);
+    if (v == NULL)
+        return NULL;
+
+    key = gdbm_firstkey(dp->di_dbm);
+    while (key.dptr) {
+        item = PyString_FromStringAndSize(key.dptr, key.dsize);
+        if (item == NULL) {
+            free(key.dptr);
+            Py_DECREF(v);
+            return NULL;
+        }
+        err = PyList_Append(v, item);
+        Py_DECREF(item);
+        if (err != 0) {
+            free(key.dptr);
+            Py_DECREF(v);
+            return NULL;
+        }
+        nextkey = gdbm_nextkey(dp->di_dbm, key);
+        free(key.dptr);
+        key = nextkey;
+    }
+    return v;
+}
+
+static int
+dbm_contains(PyObject *self, PyObject *arg)
+{
+    dbmobject *dp = (dbmobject *)self;
+    datum key;
+
+    if ((dp)->di_dbm == NULL) {
+	PyErr_SetString(DbmError,
+			"GDBM object has already been closed");
+	return -1;
+    }
+    if (!PyString_Check(arg)) {
+	PyErr_Format(PyExc_TypeError,
+		     "gdbm key must be bytes, not %.100s",
+		     arg->ob_type->tp_name);
+	return -1;
+    }
+    key.dptr = PyString_AS_STRING(arg);
+    key.dsize = PyString_GET_SIZE(arg);
+    return gdbm_exists(dp->di_dbm, key);
+}
+
+static PySequenceMethods dbm_as_sequence = {
+	0,			/* sq_length */
+	0,			/* sq_concat */
+	0,			/* sq_repeat */
+	0,			/* sq_item */
+	0,			/* sq_slice */
+	0,			/* sq_ass_item */
+	0,			/* sq_ass_slice */
+	dbm_contains,		/* sq_contains */
+	0,			/* sq_inplace_concat */
+	0,			/* sq_inplace_repeat */
+};
+
+PyDoc_STRVAR(dbm_firstkey__doc__,
+"firstkey() -> key\n\
+It's possible to loop over every key in the database using this method\n\
+and the nextkey() method. The traversal is ordered by GDBM's internal\n\
+hash values, and won't be sorted by the key values. This method\n\
+returns the starting key.");
+
+static PyObject *
+dbm_firstkey(register dbmobject *dp, PyObject *unused)
+{
+    register PyObject *v;
+    datum key;
+
+    check_dbmobject_open(dp);
+    key = gdbm_firstkey(dp->di_dbm);
+    if (key.dptr) {
+        v = PyString_FromStringAndSize(key.dptr, key.dsize);
+        free(key.dptr);
+        return v;
+    }
+    else {
+        Py_INCREF(Py_None);
+        return Py_None;
+    }
+}
+
+PyDoc_STRVAR(dbm_nextkey__doc__,
+"nextkey(key) -> next_key\n\
+Returns the key that follows key in the traversal.\n\
+The following code prints every key in the database db, without having\n\
+to create a list in memory that contains them all:\n\
+\n\
+      k = db.firstkey()\n\
+      while k != None:\n\
+          print k\n\
+          k = db.nextkey(k)");
+
+static PyObject *
+dbm_nextkey(register dbmobject *dp, PyObject *args)
+{
+    register PyObject *v;
+    datum key, nextkey;
+
+    if (!PyArg_ParseTuple(args, "s#:nextkey", &key.dptr, &key.dsize))
+        return NULL;
+    check_dbmobject_open(dp);
+    nextkey = gdbm_nextkey(dp->di_dbm, key);
+    if (nextkey.dptr) {
+        v = PyString_FromStringAndSize(nextkey.dptr, nextkey.dsize);
+        free(nextkey.dptr);
+        return v;
+    }
+    else {
+        Py_INCREF(Py_None);
+        return Py_None;
+    }
+}
+
+PyDoc_STRVAR(dbm_reorganize__doc__,
+"reorganize() -> None\n\
+If you have carried out a lot of deletions and would like to shrink\n\
+the space used by the GDBM file, this routine will reorganize the\n\
+database. GDBM will not shorten the length of a database file except\n\
+by using this reorganization; otherwise, deleted file space will be\n\
+kept and reused as new (key,value) pairs are added.");
+
+static PyObject *
+dbm_reorganize(register dbmobject *dp, PyObject *unused)
+{
+    check_dbmobject_open(dp);
+    errno = 0;
+    if (gdbm_reorganize(dp->di_dbm) < 0) {
+        if (errno != 0)
+            PyErr_SetFromErrno(DbmError);
+        else
+            PyErr_SetString(DbmError, gdbm_strerror(gdbm_errno));
+        return NULL;
+    }
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+PyDoc_STRVAR(dbm_sync__doc__,
+"sync() -> None\n\
+When the database has been opened in fast mode, this method forces\n\
+any unwritten data to be written to the disk.");
+
+static PyObject *
+dbm_sync(register dbmobject *dp, PyObject *unused)
+{
+    check_dbmobject_open(dp);
+    gdbm_sync(dp->di_dbm);
+    Py_INCREF(Py_None);
+    return Py_None;
+}
+
+static PyMethodDef dbm_methods[] = {
+    {"close",	  (PyCFunction)dbm_close,   METH_NOARGS, dbm_close__doc__},
+    {"keys",	  (PyCFunction)dbm_keys,    METH_NOARGS, dbm_keys__doc__},
+    {"firstkey",  (PyCFunction)dbm_firstkey,METH_NOARGS, dbm_firstkey__doc__},
+    {"nextkey",	  (PyCFunction)dbm_nextkey, METH_VARARGS, dbm_nextkey__doc__},
+    {"reorganize",(PyCFunction)dbm_reorganize,METH_NOARGS, dbm_reorganize__doc__},
+    {"sync",      (PyCFunction)dbm_sync,    METH_NOARGS, dbm_sync__doc__},
+    {NULL,		NULL}		/* sentinel */
+};
+
+static PyObject *
+dbm_getattr(dbmobject *dp, char *name)
+{
+    return Py_FindMethod(dbm_methods, (PyObject *)dp, name);
+}
+
+static PyTypeObject Dbmtype = {
+    PyVarObject_HEAD_INIT(0, 0)
+    "_gdbm.gdbm",
+    sizeof(dbmobject),
+    0,
+    (destructor)dbm_dealloc,            /*tp_dealloc*/
+    0,                                  /*tp_print*/
+    (getattrfunc)dbm_getattr,           /*tp_getattr*/
+    0,                                  /*tp_setattr*/
+    0,                                  /*tp_compare*/
+    0,                                  /*tp_repr*/
+    0,                                  /*tp_as_number*/
+    &dbm_as_sequence,                   /*tp_as_sequence*/
+    &dbm_as_mapping,                    /*tp_as_mapping*/
+    0,                                  /*tp_hash*/
+    0,                                  /*tp_call*/
+    0,                                  /*tp_str*/
+    0,                                  /*tp_getattro*/
+    0,                                  /*tp_setattro*/
+    0,                                  /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT,                 /*tp_xxx4*/
+    gdbm_object__doc__,                 /*tp_doc*/
+};
+
+/* ----------------------------------------------------------------- */
+
+PyDoc_STRVAR(dbmopen__doc__,
+"open(filename, [flags, [mode]])  -> dbm_object\n\
+Open a dbm database and return a dbm object. The filename argument is\n\
+the name of the database file.\n\
+\n\
+The optional flags argument can be 'r' (to open an existing database\n\
+for reading only -- default), 'w' (to open an existing database for\n\
+reading and writing), 'c' (which creates the database if it doesn't\n\
+exist), or 'n' (which always creates a new empty database).\n\
+\n\
+Some versions of gdbm support additional flags which must be\n\
+appended to one of the flags described above. The module constant\n\
+'open_flags' is a string of valid additional flags. The 'f' flag\n\
+opens the database in fast mode; altered data will not automatically\n\
+be written to the disk after every change. This results in faster\n\
+writes to the database, but may result in an inconsistent database\n\
+if the program crashes while the database is still open. Use the\n\
+sync() method to force any unwritten data to be written to the disk.\n\
+The 's' flag causes all database operations to be synchronized to\n\
+disk. The 'u' flag disables locking of the database file.\n\
+\n\
+The optional mode argument is the Unix mode of the file, used only\n\
+when the database has to be created. It defaults to octal 0666. ");
+
+static PyObject *
+dbmopen(PyObject *self, PyObject *args)
+{
+    char *name;
+    char *flags = "r";
+    int iflags;
+    int mode = 0666;
+
+    if (!PyArg_ParseTuple(args, "s|si:open", &name, &flags, &mode))
+        return NULL;
+    switch (flags[0]) {
+    case 'r':
+        iflags = GDBM_READER;
+        break;
+    case 'w':
+        iflags = GDBM_WRITER;
+        break;
+    case 'c':
+        iflags = GDBM_WRCREAT;
+        break;
+    case 'n':
+        iflags = GDBM_NEWDB;
+        break;
+    default:
+        PyErr_SetString(DbmError,
+                        "First flag must be one of 'r', 'w', 'c' or 'n'");
+        return NULL;
+    }
+    for (flags++; *flags != '\0'; flags++) {
+        char buf[40];
+        switch (*flags) {
+#ifdef GDBM_FAST
+            case 'f':
+                iflags |= GDBM_FAST;
+                break;
+#endif
+#ifdef GDBM_SYNC
+            case 's':
+                iflags |= GDBM_SYNC;
+                break;
+#endif
+#ifdef GDBM_NOLOCK
+            case 'u':
+                iflags |= GDBM_NOLOCK;
+                break;
+#endif
+            default:
+                PyOS_snprintf(buf, sizeof(buf), "Flag '%c' is not supported.",
+                	      *flags);
+                PyErr_SetString(DbmError, buf);
+                return NULL;
+        }
+    }
+
+    return newdbmobject(name, iflags, mode);
+}
+
+static char dbmmodule_open_flags[] = "rwcn"
+#ifdef GDBM_FAST
+                                     "f"
+#endif
+#ifdef GDBM_SYNC
+                                     "s"
+#endif
+#ifdef GDBM_NOLOCK
+                                     "u"
+#endif
+                                     ;
+
+static PyMethodDef dbmmodule_methods[] = {
+    { "open", (PyCFunction)dbmopen, METH_VARARGS, dbmopen__doc__},
+    { 0, 0 },
+};
+
+PyMODINIT_FUNC
+init_gdbm(void) {
+    PyObject *m, *d, *s;
+
+    if (PyType_Ready(&Dbmtype) < 0)
+	    return;
+    m = Py_InitModule4("_gdbm", dbmmodule_methods,
+                       gdbmmodule__doc__, (PyObject *)NULL,
+                       PYTHON_API_VERSION);
+    if (m == NULL)
+	return;
+    d = PyModule_GetDict(m);
+    DbmError = PyErr_NewException("_gdbm.error", NULL, NULL);
+    if (DbmError != NULL) {
+        PyDict_SetItemString(d, "error", DbmError);
+        s = PyUnicode_FromString(dbmmodule_open_flags);
+        PyDict_SetItemString(d, "open_flags", s);
+        Py_DECREF(s);
+    }
+}